import numpy as np
arr1 = np.array([1,2,3,])
print('一维数组arr1: \n',arr1)
arr2 = np.array((4.5,5.6,6.8),dtype='int32')
print('一维数组arr2: \n',arr2)
arr3 = np.array([[1,2,3],[4,5,6]], dtype='float32')
print('2*3的二维数组arr3: \n',arr3)